Gage for rotating test part for peripheral and concentricity gaging



' March 24, 1959 s OHNSON 2,878,577

G. J GAGE FOR ROTATING TEST PART FOR PERIPHERAL AND CONCENTRICITY GAGINGOriginal Filed Nov. 21, 1951 Ill" w I H 2 mi; 4'29 29 Q bd Illllli' u 4INVENTOR. SrH/vLEY 61. JoH/vso/v ZZ W HTTORNEYS GAGE FOR ROTATING TESTPART FOR PERIPH- ERAL AND CONCENTRICITY GAGING 8 Claims. (Cl. 33-199)The invention relates to a gage of relatively inexpensive constructionhaving cooperating gaging means which support a test part in gagingposition, the test part having an internal and an external surface. Thegage gages centricity between the internal and external surface, eitherof which or both may be plain or threaded. One of the gaging means is agaging roll having means for rotating the roll. Rotation of the gagingroll in turn rotates the test part in gaging position.

An object of the invention is to construct a gage of simple form whichtests for the centricity between exterior and interior portions orsurfaces of a test part throughout the circumference thereof.

Another object is to construct a gage for testing the centricity betweenan internal surface and an external threaded surface with a gaging rollhaving thread gaging ridges which are serrated.

Other objects of the invention will be more apparent from the followingdescription when taken in connection with the accompanying drawingsillustrating preferred embodiments of the invention in which:

Figure 1 is a side view of a gage showing the gaging means as used fortesting the centricity between an internal surface, shown as threaded,and an external surface, also shown as threaded;

Figure 2 is a partial plan view of the gage of Figure 1;

Figure 3 is a modified form of gage; and

Figure 4 is an enlarged view of a portion of the gaging roll.

This application is a division of the Stanley G. Johnson applicationSerial No. 257,589 filed November 21, 1951, now Patent No. 2,770,050,issued November 13, 1956.

The simpler form of gage herein is one which provides gaging means whichsupports the test part in gaging position and one of the gaging means isa gaging roll mounted for rotation and having peripheral means to rotatethe roll. Rotation of the gaging roll in turn rotates the test part whenin gaging position thereby presenting the entire circumference of thetest part to the gaging means without requiring removal of the test partfrom gaging position and its reinsertion. Many test parts are too smallto be turned with the fingers when in gaging position and heretofore hadto be removed from gaging position, then turned and reinserted into thegage in order to test another portion of the test part. Also some testparts are too short in that their length is coextensive with the lengthof the gaging means and likewise had to be removed from gaging positionin order to present another part of the test part to the gaging means.Again it is desirable to turn a threaded test part to assure properseating of the gaging means into a thread.

Figures 1 and 2 illustrate one form of construction for testing thecentricity, i.e. concentricity, or eccentricity between an exteriorthread surface and an internal thread or surface of a test part T,threaded surfaces being particularly shown. A base or gageframe9 isprovided 2,878,577 Patented Mar. 24, 1959 for mounting the gage parts.The internal gaging means may be a pin 10 carried by a pivoted frame 11mounted upon a pivot 12 carried by the gage frame. The pin is secured tothe pivoted frame by a lock screw 14 and carries a gaging surface 15which is a lateral extending peripheral portion of a corresponding ormating ex-v ternal screw thread. Stop means in the form of a stop screw16 threaded through a projection 17 limits the pivotal movement of thepivoted frame to gaging position for the gaging means.

A second or cooperating gaging means is mounted for movement towards andaway from the test part T or the pivotally mounted gaging means10, 15when in gaging position as shown in Figure 1. The cooperating gagingmeans includes at least one gaging roll 19 mounted for rotation on astud or pivot 21 and with a movable frame mounted in any suitablefashion for movement to ward and from the test part T or the gagingmeans 10, 15. The movable mounting particularly shown is provided by asecond pivoted frame 20 mounted on a pivot 22 carried by the gage frame9. A spring 23 is used to project the movable frame and hence the gagingmeans carried thereby toward the gaging means 10, 15 at gaging position.The gaging roll 10 may be adjustable upon the pivoted frame 22 by beingcarried upon a slide 24 mounted upon the pivoted frame and clamped inposition by a screw 25. For gaging screw threads on a test part, thegaging means has gaging ridges 26 to engage the thread. The gaging meansis mounted in parallel relation with the gaging surface 15 to engage atest part supported between the gaging means.

A dial indicator 28 is used to indicate the position of the pivotedframe 20 by having its operating point 29 contacting therewith which,therefore, indicates the position of the gaging means or roll 19. Theindicator indicates whether or not the test part T is the same as ordiffers from a master or perfect part and if different, it is within theallowable tolerances as to wall thickness. When the test part is rotatedwhile in gaging position the indicator will indicate the centricity andother faults.

The test part is placed upon the gaging means 10 and the pivoted frameis pivoted to swing with the test part to gaging position in contactwith the second gaging means or roll 15). The frame 11 pivots solely forinsertion of the test part into gaging position between the gagingsurface 15 and the gaging roll 19. Gaging position is on a line throughthe center of the pivot 12 and the center of the gaging roll 19. Theroll 19 may have a single thread engaging ridge 26 or several asdesired. The gaging roll is mounted for rotation on a stud 20 and isalso mounted on the stud for substantial axial movement thereon toaccommodate for ditferences in the pitch of threads or for lack ofalignment of the external and internal thread of the same pitch.

Because of the shortness of a test piece it is difficult to turn thesame in gaging position without means for turning a gaging roll. 30 atthe peak or tips of the gaging ridges 26 to prgvide projections 31 orroughness. The recess may be no more than two thousandths of an inchdeep which gives suf-v ficient irregularity so that the roll may beeasily turned by the inspectors fingers. By turning the gaging roll 19the test part T is rotated therewith while supported in gaging positionto present the entire circumference of the test part to the gagingmeans. If there is gradual movement of the indicator as the test part isrotated through a half turn, variation in the wall thickness of the testpart is indicated which variation is occassioned by eccentricity betweenthe inner surface or thread and the outer surface or thread whatever thesurface form may be on the test part. A sudden change in the indicatorreading"= The roll 19 has shallow recessesis indicative of anotherthread fault such as an irregu- I larity.

Figure 3 illustrates the invention as applied to a different form ofgage which however is basically the same as that of Figures 1 and 2. Agage frame or base 43 carries a movable frame 44, preferably pivotedandrcarried by a pivot 45 on the gage frame or base. This movable orpivoted frame carries the gaging pin with its gaging surface whichsupports and participates in gaging the test part T. A cooperatinggaging roll 19 is rotatably mounted upon a stud 21 carried by an arm 46forming a part of the gage base or frame. The gaging roll is mounted inspaced parallel relation to the gaging surface 15. An indicator 47engages the pivoted frame 44, such as an extension 48 thereof and byobserving the indicator the inspector determines the acceptability ofthe test piece. I

The gaging roll 19 has means for rotating the same. Preferably thegaging roll carried by the arm 46 has thread gaging ridges 26 of theform shown in Figure 4. By rotating the gaging roll the test part isrotated in gaging position thereby presenting the entire circumence ofthe test part to the gaging means. The pivot means or studs for thegaging roll may be the same as that of Figure 1 and hence is similarlynumbered. A spring 49 may press the pivoted frame and gaging means 10,15 upwardly towards the gaging roll 19.

Note that in the construction of Figure 3, the pivoted frame 44 isdepressed so that the test piece may be inserted on the gaging means 10,15 whereupon the pivoted frame is released to bring the test piece intocontact with the cooperating gaging roll 19 and the position of thegaging means 10, 15 or particularly the frame carrying the same isindicated by the indicator which indicates the acceptability of the testpart. The pivoted frame 44 of this construction is, therefore, movableboth for insertion of the test part between the gaging means and forproviding the movement for performing the gaging function. It isimmaterial which of the gaging means has the movement relatively to theother for insertion of the test part between the gaging means and toprovide the gaging function or operation of the test part.

In the gages described herein, the external gaging means is a gagingroll which has means for rotation of the same so that the test part whenin gaging position is rotated thereby to present its entirecircumference to the gaging means. In all constructions illustratedthere is at least one movable frame, preferably pivoted, enablinginsertion of the test part between the gaging means at gaging positionwhere the test part is supported by the gaging means and rotated by agaging roll of the gaging means.

This invention is presented to fill a need for improvements in gage forrotating test part for peripheral and concentricity gaging. It isunderstood that various modifications in structure, as well as changesin mode of operation, assembly and manner of use, may and often do occurto those skilled in the art, especially after benefiting from theteachings of an invention. Hence, it will be understood that thisdisclosure is illustrative of preferred means of embodying the inventionin useful form by explaining the construction, operation and advantagesthereof.

What is claimed is:

1. A gage for testing the centricity between an internal and a largerexternal surface providing a wall having thickness comprising a gageframe, a first gaging means carried by the gage frame for engaging aportion of the internal surface of the test part and having a lengthapproximating the length of the test part, a second gaging means carriedby the gage frame for engaging the external surface of the test part andlocated adjacent to the first gaging means and spaced therefrom adistance comparable to the wall thickness of the test part to receivethe wall therebetween, the second gaging means having a lengthapproximating the length of the test part and cooperating with the firstgaging means to provide the sole support for a test part in gagingposition and to gage the test part, at least one of the gaging meansbeing a gaging roll, means mounting the gaging roll for rotation, meansto rotate the gaging roll which thereby rotates the test part in gagingposition, means mounting at least one of the gaging means for movementtoward and away from the other to insert a test part between the gagingmeans and to gage the test part, and an indicator carried by the gageframe and connected with the gaging means having a gaging movement.

2. A gage for testing the centricity between an internal and a largerexternal surface providing a wall having thickness comprising a gageframe, a first gaging means carried by the gage frame for engaging aportion of the internal peripheral surface of the test part, the firstgaging means being a pin having a gaging surface to engage a portion ofthe internal surface and having a length approximating the length of thetest part, a second gaging means carried by the gage frame for engagingthe external surface of the test part and located adjacent to the firstgaging means and spaced therefrom a distance comparable to the wallthickness of the test part to receive the wall therebetween, the secondgaging means having a length approximating the length of the test partand cooperating with the first gaging means to provide the sole supportfor a test part in gaging position and to gage the test part, the secondgaging means being a gaging roll, means mounting the gaging roll forrotation, means to rotate the gaging roll which thereby rotates the testpart in gaging position, means mounting at least one of the gaging meansfor movement toward and away from the other to insert a test partbetween the gaging means and to gage the test part, and an indicatorcarried by the gage frame and connected with the gaging means having agaging movement.

3. A gage for testing the centricity between an internal and an externalthreaded surface comprising a gage frame, a pivot carried by the gageframe, a pivoted frame mounted on the pivot, a gaging pin carried by thepivoted frame spaced from the pivot therefor, a portion of a threadcarried by the gaging pin conforming to the internal thread for engaginga portion of the internal thread of the test part, a second pivotcarried by the gage frame, a pivoted frame carried by the second pivot,a gaging roll stud carried by the second pivoted frame spaced from theframe pivot, a gaging roll carried by the stud for rotation and axialmovement thereon for engaging the external threaded surface of the testpart and cooperating with the first gaging means to support a test partin gaging position and to gage the test part, means to rotate the gagingroll which thereby rotates the test part in gaging position, and anindicator carried by the gage frame and engaging the second frame toindicate the position thereof and the gaging roll.

4. A gage for testing the centricity between an internal surface and anexternal threaded surface comprising a gage frame, a first gaging meanscarried by the gage frame for engaging an axially extending portion ofthe internal peripheral surface of the test part, a second gaging meanscarried by the gage frame for engaging the external thread of the testpart and cooperating with the first gaging means to support a test partin gaging position and to gage the test part, the second gaging meansbeing a gaging roll having thread gaging ridges around its periphery,means mounting the gaging roll for rotation, serrations on theperipheral peaks of the gaging ridges to rotate the gaging roll whichthereby rotates the test part in gaging position, means mounting atleast one of the gaging means for movement toward and away from theother to insert a test part between the gaging means and to gage thetest part, and an indicator carried by the gage frame and connected withthe gaging means having a gaging movement.

5. A gage as in claim 4 including a pivoted frame for movement to gagingposition, pivotally mounted on the gage frame and carrying the firstgaging means and the second gaging means being mounted for gagingmovement towards and from the first gaging means to gage a test part.

6. A gage as in claim 4 including a pivoted frame pivotally mounted onthe gage frame and carrying the first gaging means for movement togaging position and to and from the gaging roll for gaging movement.

7. A gage for testing an internally and externally threaded test parthaving length comprising a gage frame,

a pivot carried by the gage frame, a pivoted frame mounted on the pivotmovable to and from gaging position, a gaging pin carried by the pivotedframe spaced from the pivot therefor, a first gaging means carried bythe gaging pin having a threaded surface conforming to the internalthread on the test part for engaging the internal thread, a gaging rollstud, means mounting the gaging roll stud on the gage frame spaced fromthe frame pivot and the gaging pin when in gaging position and formovement towards and away from the first gaging means on the gaging pin,a gaging roll mounted on the stud for rotation thereon for engaging theexternal thread of the test part and cooperating with the first gagingmeans when in gaging position, and an indicator carried by the gageframe and engaging the mounting means to indicate the position of thegaging roll.

8. A gage for testing an internally and externally threaded test partcomprising a gage frame, a pivot carried by the gage frame, a pivotedframe mounted on the pivot movable to and from gaging position, a gagingpin carried by the pivoted frame spaced from the pivot therefor, a firstgaging means carried by the gaging pin having a threaded surfaceconforming to the internal thread on the test part for engaging theinternal thread, a gaging roll stud, a second pivoted frame mounting thegaging roll stud on the gage frame spaced from the frame pivot and thegaging pin when in gaging position and for movement towards and awayfrom the first gaging means on the gaging pin, a gaging roll mounted onthe stud for rotation thereon for engaging the external thread of thetest part and cooperating with the first gaging means when in gagingposition, and an indicator carried by thegage frame and engaging thesecond pivoted frame to indicate the position of the gaging roll.

References Cited in the file of this patent UNITED STATES PATENTS

